Fresh air damper arrangement for room air conditioner

ABSTRACT

An air conditioning unit having a louvered fresh air opening located in an evaporator blower scroll housing side wall in the vertical exhaust air passageway such that recirculated room air from the blower wheel is passed over a plurality of angularly disposed horizontally extending louvers cooperating with the upward flow of air in the scroll housing thereover present Venturi creating deflectors which draw outside fresh or make-up air into the scroll housing to be mixed with the recirculated conditioned room air. A damper door and overlying three-sided channel duct are positioned on the condenser compartment side of the louvers such that when the door is opened it forms an elbow duct scoop-like air intake conduit directing a portion of the outside air flow through the louvered scroll housing opening and when the door is closed the open-sided channel duct presents minimal interference with the outside air being drawn into the condenser compartment by fan means for cooling the condenser.

ited States atent 1191 Loos et al.

[ 1 Feb. 19., 1974 [75] Inventors: John H. Loos, Dayton; Emerson L.

Wark, Vandalia, both of Ohio General Motors Corporation, Detroit, Mich.

Aug. 10, 1972 [73] Assignee:

[51] Int. Cl. lF25d 23/12 [58] Field of Search 62/427, 428, 429, 262

Primary Examiner-William J. Wye Attorney, Agent, or Firm-Edward P.Barthel References Cited UNITED STATES PATENTS Cohler 62/262 62/26262/427 Webster 62/427 5 7] ABSTRACT An air conditioning unit having alouvered fresh air opening located in an evaporator blower scrollhousing side wall in the vertical exhaust air passageway such thatrecirculated room air from the blower wheel is passed over a pluralityof angularly disposed hori zontally extending louvers cooperating withthe upward flow of air in the scroll housing thereover present Venturicreating deflectors which draw outside fresh or make-up air into thescroll housing to be mixed with the recirculated conditioned room air. Adamper door and overlying three'sided channel duct are positioned on thecondenser compartment side of the louvers such that when the door isopened it forms an elbow duct scoop-like air intake conduit directing aportion of the outside air flow through the louvered scroll housingopening and when the door is closed the open-sided channel duct presentsminimal interference with the outside air being drawn into the condensercompartment by fan means for cooling the condenser.

3 Claims, 5 Drawing [Figures FRESII AIR DAMPER ARRANGEMENT FOR ROOM AIRCONDITIONER This invention relates to a fresh air damper assembly for aroom air conditioning unit and in particlar to an improved damper doorand baftle apparatus for controlling the admittance of fresh or make-upair into the evaporator blower scroll housing of the unit.

Air conditioner units employ many methods of bringing in and controllingthe flow of fresh air for mixture with the recirculated room air todissipate smoke, cooking and other foul odors which may accumulate inthe conditioned area. For example, US. Pat. No. 3,305,162, issued Feb.21, 1967 to W. B. Hall, Jr. discloses a damper door which in oneposition is projected into a room air discharge chamber as an airdeflector to create a zone of low pressure by a Venturi action orsuction which acts to draw outside fresh air into the chamber formixture with the air stream discharged from the evaporator blower intothe room being conditioned. The prior art, however, fails to teach asatisfactory damper arrangement for drawing fresh air directly into theevaporator blower scroll casing for mixture with the recirculated airtherein prior to its exhaust into duct means for subsequent dischargeinto the room.

It is therefore an object of this invention to provide a simple,efficient damper arrangement for the evaporator blower scroll housing ofa room air conditioning unit allowing the blower wheel to draw in freshor make-up air through a first opening in the weather casing and thenceinto a second louvered opening in the blower scroll side opening locatedin the wall of the widening spiral passageway in combination with adamper door and cooperating channel-shaped duct such that when openedthe door closes one end of the channel-shaped duct forming a scoop-likedihedral conduit directing outside air through the louvered secondopening into the scroll widening spiral passageway and upon closure ofthe door the channel-shaped duct presents minimal obstruction turbulenceto the flow of outside air being drawn into the condenser chamber by thecondenser fan.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

IN THE DRAWINGS FIG. I is a top plan view of a room air conditionerhaving an arrangement according to the invention;

FIG. 2 is an enlarged fragmentary horizontal section taken along theline 2-2 of FIG. 3;

FIG. 3 is an enlarged fragmentary elevational plan view taken along thelines 3-3 of FIG. 1;

FIG. 4 is a vertical sectional view taken along the lines 4-4 of FIG. 3;

FIG. 5 is an enlarged perspective view of the door hinge clip.

Referring now to the drawings and more particularly to FIG. I, there isshown a window air conditioner unit having a weather casing enclosing asealed motor compressor unit 22, a support bracket 24 for a fan motor25, having a propeller fan 26 mounted on one end of motor shaft 27 whichdraws in outside air via suitable side louvers 28 and 29 through acondenser 30 and discharge through louvers 31 at the back of the casing20 to the outside air. A suitable condenser shroud 35 is provided with abeIlmouth propeller fan orifice 32 to define a condenser air chamber 33.

A transverse upright bulkhead partition 34 extends across the casing 20to divide the interior of the air conditioning unit into an innerevaporator compartment 36 and the outer compartment 33 exposed to theoutside air. The bulkhead partition 34 includes vertical wall sections39 and 40 and top wall section 411. Spaced below the top wall 411 is ahorizontal shelf, partially indicated at 42 in FIG. 3, which togetherwith the end walls 43 and 44 define an upper room air discharge chamber46 having a conditioned air outlet 48 extending across the front of theair conditioning unit.

An evaporator 56 is located in front of a centrifugal blower, includinga blower wheel. SI mounted on the other end of the electric motor shaft27 within a blower scroll housing 52 which is generally spiral in crosssection. For further details of a typical scroll housing structurereference should be had to aforementioned Hall US. Pat. No. 3,305,162,the disclosure of which is incorporated by reference herein. The roomair enters the scroll housing through a bellmouth inlet orifice 53 inits inner sidewall 54 and is directed into a generally vertical exhaustpassageway 49 having a widening spiral form leading to scroll air outletopening 56 defined by skewed curled edge cutoff 57 at the throat sectionof the scroll housing. The scroll housing outer side wall is formed bypartition wall section 40 which has an opening through which the fanmotor shaft 27 extends so as to position the blower wheel 51asymmetrically within the scroll housing 52 parallel to the spiral wall55, with the blower wheel 54 having forwardly curved blades 59 forproducing the maximum high velocity discharge when driven in acounterclockwise direction (FIG. 3) by the motor 25. The sealed motorcompressor unit 22, the condenser 30 and the evaporator 50 are connectedtogether in an operative refrigerant circuit such as may be similar tothat shown in the Gould et al US. Pat. No. 2,945,362, issued July 19,1960.

The scroll housing outer side wall 40 has a generally rectangular freshair intake opening 60 located in the widening spiral form exhaustpassageway of the scroll housing 52. A louvered insert member 61 whichin the form shown is integrally molded of plastic material is suitablysecured in the opening 60 such as by cementing material and has aplurality of upwardly and inwardly directed horizontally disposedlouvers 62. By virtue of the blower wheel 51 directing air upwardly overthe louvers in the passageway 49 a zone of low pressure is created by aventuri action which will draw in outside air through a first opening inthe form of casing side louvers 29 and a second opening 60 into theoutflowing air stream forced through the scroll housing outlet 56 intodischarge chamber 46.

As best shown in FIG. 2, a closure member or damper door is provided forthe louvered opening 66 located on the outer compartment 38 side of thewall 40 and may be selectively opened and closed for alternativelymixing fresh or outside makeup with recirculated room air either with orwithout cooling circulated by the blower 34.

In the preferred embodiment the door 76 is formed from a sheet metalblank having a base panel 63 the marginal edges of which have inturnedright-angled side flange 64, obtuse angled side flange 65, andrightangled end flanges 66 defining a pan-like member into which isreceived a conforming rectangular sheet of sponge-like foam sealingmaterial such as polyurethane foam 67 of sufficient thickness, aboutone-quarter inch in the disclosed form, having a pressure sensitiveadhesive removable backing for securing to the inner surface of the basepanel 63 to effectively seal the outer edge of a substantiallyrectangular frame portion 68 integrally molded on the outer side of thelouvered insert member 61. If desired a screening 71 can be inserted inthe frame 68 to prevent the entrance of bugs or other foreign matterwithin the scroll casing.

As best seen in FIGS. 2, and 6, a pair of hinge fasteners 72 and 73 areused in the disclosed embodiment to hingedly connect the door 70 to theouter wall 40. The hinge fasteners 72 comprise a U-shaped resilient clipportion 74 which snaps over integrally molded upper and lower ribmembers 75 and '76 on the outer wall 40 and are securely retained on theribs by lanced inwardly directed pairs of barbs 77 and 78 struck fromthe clip adjacent its open end. Each hinge fastener 72 and 73 has anelongate outwardly extending integral arm 80 disposed at right angles tothe U-shaped clip 74 with the outer end of the arm being bent to providean inwardly curved finger 82 having a hook-like end thereon forextending into elongated apertures 84 located along the obtuse angledside flange 65 of the door. The side flange 65 is formed at an obtuseangle to allow for clearance with the frame 68 when the door is moved toits open position. Narrow tabs 86 are lanced and bent outwardly from thearms 80 to provide stop means to limit the amount of insertion of thehooklike fingers 82 into the elongated door apertures 84.

Fresh air duct means in the form of an inverted openended three-sidedbox-shaped channel duct 90, preferably formed of sheet metal, has anoutwardly spaced vertical back wall 92 overlying the intake louveredopening 61 and inwardly extending upper and lower walls 94 and 96 eachhaving an outwardly directed mounting foot flange shown at 98 and 100 inFIG. 4. The back wall or baffle plate 92 is of sufficient dimension soas to span the louvered insert opening 61 in a lengthwise direction andis positioned in a plane substantially parallel to the plane of door 70when in its closed position. The foot flanges 98 and 100 have verticallyoffset holes formed therein for the reception of screws 102 for securingthe channel-shaped duct member 90 to the wall 40. lt'will be noted inFIG. 2 that the baffle plate 92 is provided with an outwardly directedright-angled air divider flange 104 substantially parallel with thesides of the casing 20. The air divider flange 104 is positioned to besubstantially co-planar with the free edge side flange 64 of the doorwhen in its closed position with free edge flange 64 contacting the backwall 92 at an angle A of about 45 degrees, as shown in phantom lines inFIG. 2, to form a scoop-like elbow duct air intake for capturing aportion of the outside air entering through the first air opening 29 ofthe air conditioner casing 20.

The air divider flange 104 serves as a cut-off to separate the airstream entering through first intake opening 29 and assists inpreventing the negative pressure in compartment 38 from drawing the bulkof the incoming fresh air away from the entrance 106 of channel duct 90for passage through condenser fan orifice 32. It will be noted in FIG. 4that the channel duct 90 has a vertical dimension to provide a clearancespace 108 between its horizontal walls 94, 96 and the door end flanges66 to insure against vibrational contact therebetween and therebyeliminate a possible source of noise.

The louvers 62 comprise a series of horizontally extending upwardly andinwardly directed baffles which divide the entering air path throughsecond air opening 60 into a plurality of vertical portions so that thefresh make-up air is directed toward the upper scroll outlet 56. With alouvered arrangement of this type, wherein the louvers are separated,negative pressures created in the blower scroll housing 52 are equalizedover the inner face of the opening 61) so as to spread the air evenlyacross the entire height thereof so that fresh air is drawn into thescroll housing for blending with the recirculated room air with aminimum of turbulence.

A fresh air push-pull control slide 1 16 with flange tab 1 17 isprovided on the face of the unit to permit control of the fresh airdamper assembly through means of a stiff wire 1 18 which has a sheathedportion 128 extending through a suitable opening in the casing 20, wall54 and elongated opening 124 in wall 411 with the wire 118 having ahooked-end 126 (FlG. 2) for insertion through a door opening 122adjacent the side flange 64. Thus, as shown in FIG. 2 the door is closedby moving tab 117 to the left causing a pull-force on the wire 1 18 andwhen it is desired to open the door the tab 117 is moved to the leftcausing a push-force on the wire to move the door to its open phantomline position in FIG. 2. An outwardly directed protrusion 129 is formedin the baffle plate 92' to allow the hooked end 126 to be received inthe protrusion permitting the door 70 to be opened to its maximum extentas shown in FIG. 2. In addition inwardly grooved gussets 130 andoutwardly grooved gussets 131 are formed at the corner juncture of thechannel-shaped baffle duct to impart rigidity thereto.

in the exemplified embodiment the blower wheel 51 is arranged in thescroll housing and by means of spokes 132 and centered hub 133 the shaft27 is driven in a counterclockwise direction (FIG. 3) as indicated bythe arrow 134. The forwardly curved blower wheel blades 59 cause routingof the high velocity air flowing in passageway 49 to be directedupwardly over the horizontal angularly disposed louvers 62 to provide aseries of Venturi creating deflectors for drawing in fresh air throughsecond fresh air intake opening in the form of louvered insert 61. Thedecrease in air pressure relative to the air pressure of the fresh airbeing directed through the scoop-like elbow duct 90 arrangement createsa negative air differential which assists in drawing secondary or freshair through the louvered insert opening 61 for mixture with primary roomair being routed over the louvers 62 for subsequent discharge throughthe scroll exhaust outlet 56.

One of the principal features of the applicants invention results fromthe fact that when the door 78 is in its closed position the open-endedchannel-shaped duct member 90 provides a minimum of obstruction orturbulence to outside air being drawn into the outer chamber 38 by thecondenser fan 26 for movement through the bell-shaped orifice 32.

It will be noted that the upstream edges of the upper, lower and backwalls 94, 96 and 92, respectively, are positioned in close proximity tothe first louvered air intake opening 29 so as to envelop a portionthereof to enable the channel duct 90 to direct a substantial quantityof fresh air into the scroll housing when the door 70 is opened with itsvertical free flanged edge contacting the back wall 92 approximatelymidway between its upstream edge, in the form of flange 1G4, and itsdownstream edge terminating a short distance outboard of the door hingeapertures 84.

While the embodiment of the present invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted.

We claim:

1. In a room air conditioning unit, the combination comprising: a casingenclosing a condenser compartment and an evaporator compartmentseparated by a transverse partition, a first intake opening in a sidewall of said casing and positioned for delivery of outside fresh airinto said condenser compartment, said partition forming the outervertical side wall of a centrifugal impeller scroll housing, said scrollhousing having an inner side wall spaced therefrom including an airintake orifice therein for receiving a stream of recirculated room airdrawn through said evaporator compart ment for subsequent discharge viathe scroll housing exhaust passage into the room, a second rectangularfresh air intake opening in said scroll housing outer side wall having aplurality of inwardly and upwardly in clined horizontally disposedlouvers extending into said scroll housing air exhaust passage, arectangular damper door pivotally disposed on the condenser compartmentside of said scroll housing outer side wall closing said second freshair intake opening, selective actuator means for moving said doorbetween its closed position and an open position inclined outwardly intothe path of the inward flow of fresh air flow through said first intakeopening, duct means supported on said partition in the form of athree-sided box-like channel having horizontal upper and lower walls anda vertical back wall overlying said second intake opening, said channelback wall spaced rearwardly of said second intake opening so as to belocated in a plane parallel to the plane of said door in its closedposition; said upper, lower and back walls of said channel ductpresenting a minimum of obstruction to the incoming flow of condensercooling outside air when said door is in its closed position, said doorwhen in its opened position having its free vertical edge positionedcontacting said channel duct back wall so as to form with said upper andlower walls a scoop-like elbow duct to direct a portion of the fresh airentering through said first intake opening to flow through said secondopening, said louvers cooperating with the upward flow of recirculatedair in said scroll-housing exhaust passage thereover presenting Venturicreating deflectors whereby fresh air is drawn into said blower scrollhousing for mixture with the flow of recirculated room air.

2. In a room air conditioning unit, the combination comprising: a casingenclosing a condenser compartment and an evaporator compartmentseparated by a transverse partition, a first intake opening in a sidewall of said casing and positioned for delivery of outside fresh airinto said condenser compartment, said partition forming the outervertical side wall of a centrifugal impeller scroll housing, said scrollhousing having an inner side wall spaced therefrom including an airintake orifice therein for receiving a stream of recirculated room airdrawn through said evaporator compartment for subsequent discharge fromsaid scroll housing into the room, said centrifugal impeller comprisinga blower wheel having its center of rotation eccentrically arrangedwithin said scroll housing defining a vertical air exhaust passageway ofwidening spiral form, a second rectangular fresh air intake opening insaid scroll housing outer side wall having a plurality of inwardly andupwardly inclined horizontally disposed louvers extending into saidscroll housing air exhaust passage, a rectangular damper door pivotallydisposed on the con denser compartment side of said scroll housing outerside wall closing said second fresh air intake opening, selectiveactuator means for moving said door between its closed position and anopen position inclined outwardly at an angle of approximately 45 intothe path of the inward flow of fresh air flow through said first intakeopening, duct means supported on said partition in the form of anopen-ended box-like channel having horizontal upper and lower walls anda vertical back wall overlying said second intake opening, said channelback wall spaced rearwardly of said second intake opening so as to belocated in a plane parallel to the plane of said door in its closedposition; the upstream edges of said upper, lower and back walls of saidchannel duct located in close proximity to said casing side wall so asto envelop a portion of said first intake opening, said door when in itsopened position having its free vertical edge positioned contacting saidchannel duct back wall so as to form with said upper and lower walls ascoop-like elbow duct to direct a portion of the fresh air enteringthrough said first intake opening to flow through said second opening,said upstream edge of said channel back wall having an outwardlydirected air divider flange formed therein substantially parallel tosaid casing side wall to increase the amount of air flow into saidchannel duct when said door is in its opened position, said louverscooperating with the upward flow of recirculated air in saidscroll-housing exhaust passage thereover presenting Venturi creatingdeflectors whereby fresh air is drawn into said blower scroll housingfor mixture with the flow of recirculated room air.

3. in a room air conditioning unit, the combination comprising: a casingenclosing a condenser compartment and an evaporator compartmentseparated by a transverse partition, 21 first fresh air intake openingin said casing positioned for delivery of outside air into saidcondenser compartment, a centrifugal impeller scroll housing in saidevaporator compartment includ ing inner and outer side walls andincluding a vertically disposed air exhaust passage, an air inletorifice in said scroll housing inner side wall concentric with saidblower wheel communicating with said evaporator compartment forreceiving a stream of recirculated air withdrawn from the room into saidevaporator compartment for subsequent discharge into the room, a secondrectangular fresh air intake opening in said scroll housing outer sidewall communicating with said condenser compartment, said second intakeopening having a plurality of horizontally extending parallel louversangularly disposed directing the flow of fresh air upwardly into saidblower scroll air exhaust passage, a rectangular damper door, means forpivotally support ing said door on said scroll housing outer side wallcovering said second fresh air intake opening including a plurality ofhinge fasteners comprising a U-shaped resilient clip portion which snapsover integrally molded rib members on said scroll housing outer sidewall, each said hinge fastener having an elongate integral arm disposedat right angles to said clip, the outer end of said arm being bent toprovide an inwardly curved finger extending into an elongated aperturein said door, said clip arm having a lanced tab bent outwardly therefromproviding stop means to limit the amount of insertion of said finger insaid door aperture, selective actuator means for moving said doorbetween its closed position and an open position inclined outwardly atan angle of approximately 45 into said condenser compartment in the pathof the inward flow of fresh air through said first fresh air intakeopening, duct means supported on said blower scroll outer side wall inthe form of a threesided box-like channel having horizontal upper andlower walls and a vertical back wall overlying said second intakeopening, said channel back wall spaced rearwardly of said second intakeopening so as to be located in a plane parallel to the plane of saiddoor in its closed position, the upstream edges of said upper, lower andback walls of said channel duct located in close proximity to saidcasing side wall presenting a minimum of obstruction to the incomingfresh air flow through said first intake opening when said door is inits closed position, said door when in its opened position having itsvertical free edge contacting said channel back wall approximatelymidway between its upstream and downstream vertical edges so as to formwith said upper and lower channel walls a scoop-like elbow duct causinga portion of the fresh air entering through said first intake opening toflow through said second opening into said scroll housing.

1. In a room air conditioning unit, the combination comprising: a casingenclosing a condenser compartment and an evaporator compartmentseparated by a transverse partition, a first intake opeNing in a sidewall of said casing and positioned for delivery of outside fresh airinto said condenser compartment, said partition forming the outervertical side wall of a centrifugal impeller scroll housing, said scrollhousing having an inner side wall spaced therefrom including an airintake orifice therein for receiving a stream of recirculated room airdrawn through said evaporator compartment for subsequent discharge viathe scroll housing exhaust passage into the room, a second rectangularfresh air intake opening in said scroll housing outer side wall having aplurality of inwardly and upwardly inclined horizontally disposedlouvers extending into said scroll housing air exhaust passage, arectangular damper door pivotally disposed on the condenser compartmentside of said scroll housing outer side wall closing said second freshair intake opening, selective actuator means for moving said doorbetween its closed position and an open position inclined outwardly intothe path of the inward flow of fresh air flow through said first intakeopening, duct means supported on said partition in the form of athree-sided box-like channel having horizontal upper and lower walls anda vertical back wall overlying said second intake opening, said channelback wall spaced rearwardly of said second intake opening so as to belocated in a plane parallel to the plane of said door in its closedposition; said upper, lower and back walls of said channel ductpresenting a minimum of obstruction to the incoming flow of condensercooling outside air when said door is in its closed position, said doorwhen in its opened position having its free vertical edge positionedcontacting said channel duct back wall so as to form with said upper andlower walls a scoop-like elbow duct to direct a portion of the fresh airentering through said first intake opening to flow through said secondopening, said louvers cooperating with the upward flow of recirculatedair in said scroll-housing exhaust passage thereover presenting Venturicreating deflectors whereby fresh air is drawn into said blower scrollhousing for mixture with the flow of recirculated room air.
 2. In a roomair conditioning unit, the combination comprising: a casing enclosing acondenser compartment and an evaporator compartment separated by atransverse partition, a first intake opening in a side wall of saidcasing and positioned for delivery of outside fresh air into saidcondenser compartment, said partition forming the outer vertical sidewall of a centrifugal impeller scroll housing, said scroll housinghaving an inner side wall spaced therefrom including an air intakeorifice therein for receiving a stream of recirculated room air drawnthrough said evaporator compartment for subsequent discharge from saidscroll housing into the room, said centrifugal impeller comprising ablower wheel having its center of rotation eccentrically arranged withinsaid scroll housing defining a vertical air exhaust passageway ofwidening spiral form, a second rectangular fresh air intake opening insaid scroll housing outer side wall having a plurality of inwardly andupwardly inclined horizontally disposed louvers extending into saidscroll housing air exhaust passage, a rectangular damper door pivotallydisposed on the condenser compartment side of said scroll housing outerside wall closing said second fresh air intake opening, selectiveactuator means for moving said door between its closed position and anopen position inclined outwardly at an angle of approximately 45* intothe path of the inward flow of fresh air flow through said first intakeopening, duct means supported on said partition in the form of anopen-ended box-like channel having horizontal upper and lower walls anda vertical back wall overlying said second intake opening, said channelback wall spaced rearwardly of said second intake opening so as to belocated in a plane parallel to the plane of said door in its closedposition; the upstream edges of said upper, lower and back walls of saidchannel duct located in close proximity to said casing side wall so asto envelop a portion of said first intake opening, said door when in itsopened position having its free vertical edge positioned contacting saidchannel duct back wall so as to form with said upper and lower walls ascoop-like elbow duct to direct a portion of the fresh air enteringthrough said first intake opening to flow through said second opening,said upstream edge of said channel back wall having an outwardlydirected air divider flange formed therein substantially parallel tosaid casing side wall to increase the amount of air flow into saidchannel duct when said door is in its opened position, said louverscooperating with the upward flow of recirculated air in saidscroll-housing exhaust passage thereover presenting Venturi creatingdeflectors whereby fresh air is drawn into said blower scroll housingfor mixture with the flow of recirculated room air.
 3. In a room airconditioning unit, the combination comprising: a casing enclosing acondenser compartment and an evaporator compartment separated by atransverse partition, a first fresh air intake opening in said casingpositioned for delivery of outside air into said condenser compartment,a centrifugal impeller scroll housing in said evaporator compartmentincluding inner and outer side walls and including a vertically disposedair exhaust passage, an air inlet orifice in said scroll housing innerside wall concentric with said blower wheel communicating with saidevaporator compartment for receiving a stream of recirculated airwithdrawn from the room into said evaporator compartment for subsequentdischarge into the room, a second rectangular fresh air intake openingin said scroll housing outer side wall communicating with said condensercompartment, said second intake opening having a plurality ofhorizontally extending parallel louvers angularly disposed directing theflow of fresh air upwardly into said blower scroll air exhaust passage,a rectangular damper door, means for pivotally supporting said door onsaid scroll housing outer side wall covering said second fresh airintake opening including a plurality of hinge fasteners comprising aU-shaped resilient clip portion which snaps over integrally molded ribmembers on said scroll housing outer side wall, each said hinge fastenerhaving an elongate integral arm disposed at right angles to said clip,the outer end of said arm being bent to provide an inwardly curvedfinger extending into an elongated aperture in said door, said clip armhaving a lanced tab bent outwardly therefrom providing stop means tolimit the amount of insertion of said finger in said door aperture,selective actuator means for moving said door between its closedposition and an open position inclined outwardly at an angle ofapproximately 45* into said condenser compartment in the path of theinward flow of fresh air through said first fresh air intake opening,duct means supported on said blower scroll outer side wall in the formof a three-sided box-like channel having horizontal upper and lowerwalls and a vertical back wall overlying said second intake opening,said channel back wall spaced rearwardly of said second intake openingso as to be located in a plane parallel to the plane of said door in itsclosed position, the upstream edges of said upper, lower and back wallsof said channel duct located in close proximity to said casing side wallpresenting a minimum of obstruction to the incoming fresh air flowthrough said first intake opening when said door is in its closedposition, said door when in its opened position having its vertical freeedge contacting said channel back wall approximately midway between itsupstream and downstream vertical edges so as to form with said upper andlower channel walls a scoop-like elbow duct causing a portion of thefresh air entering through said first intake opening to flow throughsaid second opening into said Scroll housing.